How much of a 100g sample of 198 Au is left after 8.10 days if its half-life is 2.70 days?

12.5

The half of 42K is 12.4 hours. How much of 750 g sample is left after 62 hours?

23.4375

What is the half-life of 99Tc if a 500g sample decays to 62.5 g in 639,000 years?

213,000

The half-life of 232Th is 1.4 x 10^10 years. If there are 25.0 g of the sample left after 2.8 x 10^10 years, how many grams were in the original sample?

100g

A 50 g sample of 16N decays to 12.5 g in 14.4 seconds. What is the half-life?

7.2

There are 5.0 g of 131I left after 40.35 days. How many grams were in the original sample if its half-life is 8.07 days

150g

Tracers

Because radioisotopes chemically resemble the stable isotopes of the same element they can be used as tracers to follow the course of a reaction

Radioactive isotopes used for diagnostic purposes

Should have SHORT half-lives and be QUICKLY eliminated from the body

I-131

Thyroid Disorders

Technetium-99

Pinpoint Brain tumors

Co-60

Treating Cancer

C-14 to C-12 ratio

Date formerly living organisms

Example of Carbon (14-12) Dating

When a tree takes in CO2, it takes in C-14 and C-12. When the ratio of C-14 to C-12 is the same ratio as in the atmosphere. But when the tree dies the C-14 decays and is not replaced and thereby changing the ratio over time

U-238 to Pb-206 ratio

Dates geological formations, such as the age of mineral

What is the nuclear decay mode for the change from Pb-214 to Bi-214

Beta Decay

Industrial Measurements

Radioactive isotopes can measure the thickness of many industrial products

Kill Bacteria

Radiation allows food to be stored longer by eliminating bacteria, yeast, molds, and insects from food

Induced Artificial Transmutation

Artificial transmutation can be induced by the BOMBARDMENT of the nucleus by high-energy particles

Particle Accelerators

Cyclotron or synchrotronUse electric and magnetic fields to provide charged particles, such as an alpha particle with sufficient kinetic energy to overcome electrostatic forces and penetrate a target nucleus

Second way of Artificial Transmutation

Occurs when a neutron collides with a target nucleus. The neutrons can be obtained as by-products of nuclear reactors, since the neutron doesn't have a charge, it is not repelled by the target nucleus.

Nuclear Reactions vs. Chemical Reactions

The energy released during nuclear reactions is far greater than the energy given off from chemical reactions

Products vs. Reactants of a Nuclear Reaction

Products have less mass than the reactants

Mass defect

The error between the recants and the products has been converted into energy

Nuclear Fission and Nuclear Fusion

Reactions utilizing sources of energy

Nuclear Fission

The SPLITTING of a nucleus into smaller fragments, accompanied by the release of neutrons and a large amount of energy- Results from Neutron Capture - Result is unstable

Fission Reaction

Must be PU-239, U-235, or U-233!- Has one nuclear isotope combine with a neutron to form two real isotopes, a neutron, and energy - The reaction is controlled and able to produce useful energy